Cora Limestone Member
Lithostratigraphy: Pope Megagroup >>Clore Formation >>Cora Limestone Member
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Chesterian Series >>Elviran Stage
Allostratigraphy: Kaskaskia Sequence
Primary source
Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.
Contributing author(s)
Elwood Atherton, Charles Collinson, and Jerry A. Lineback
Name
Original description
The Cora Limestone Member of the Clore Formation (Swann, 1963, p. 40-41).
Derivation
Named for Cora, Jackson County.
Other names
History/background
Type section
Type location
The type section of the Cora Limestone Member is at the mouth of Degonia Creek Hollow (SW SE 16, 8S-5W).
Type author(s)
Type status
Reference section
Reference location
Reference author(s)
Reference status
Stratigraphic relationships
The Cora Limestone Member is the lowest member of the Clore Formation.
Extent and thickness
The Cora is 15-45 feet thick.
Lithology
It varies from dominantly limestone to dominantly shale. In both facies, the Cora is interbedded limestone and shale and locally contains sandstone lenses.
Core(s)
Photograph(s)
Contacts
Well log characteristics
Fossils
A zone in the Cora Member in which the limestone surfaces are covered with delicate branching bryozoans is the Batostomella nitidula Peak Zone (S. Weller, 1926).
Age and correlation
Environments of deposition
Economic importance
Remarks
References
SWANN, D. H., 1963, Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.
WELLER, STUART, 1926, Faunal zones in the standard Mississippian section: Journal of Geology, v. 34, p. 320-335.
ISGS Codes
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